Device for applying filters to cigarettes

ABSTRACT

Filter tips are applied to cigarettes by a device equipped with a conveying roller ( 9 ) on which assemblies ( 4 ) composed of two cigarettes ( 5 ) and a double length filter plug ( 6 ) placed between them are united with tipping papers ( 11 ), also with a flexible rolling conveyor ( 12 ) looped around first and second pulleys ( 16, 18 ) and combining with the roller ( 9 ) to create a concave channel ( 13 ) along which a tipping paper is rolled around the relative filter. The rolling surface of the flexible conveyor ( 12 ) is faced with metal cleats ( 24 ) ordered transversely one beside the next. To ensure that the conveyor ( 12 ) runs concentrically with the roller ( 9 ) and maintain a constant depth along the channel ( 13 ), the device is equipped with magnets ( 30 ) and guide wheels ( 33 ) positioned on the side of the flexible conveyor ( 12 ) opposite from the channel ( 13 ) in such a way that the magnets ( 30 ) will interact with the cleats ( 24 ) and with blocks ( 26 ) and screws ( 27 ) by which the cleats are clamped to the conveyor ( 12 ).

TECHNICAL FIELD

The present invention relates to a device for applying filters to cigarettes, and in particular to a device by which cigarettes and filters are joined together with gummed tipping papers.

BACKGROUND ART

Conventionally, filters are applied to cigarettes by machines referred to as filter tip attachments, in a succession of steps briefly described below.

Cigarettes are ordered in pairs, with the two cigarettes of each pair axially aligned and a filter plug double the length of a tip for one cigarette interposed between them in end-to-end contact, likewise axially aligned. The group or assembly made up of the single cigarettes and the filter plug is joined permanently by means of a gummed tipping paper wrapped around the filter plug and overlapping each of the corresponding cigarette ends by about three millimetres.

According to prior art practice, these assembling and joining steps can be brought about on the surface of a conveying drum, onto which the aforementioned assemblies and the gummed papers are directed, in an operation whereby each assembly is rolled against a relative paper. The rolling action is induced along a passage delimited on the one hand by the drum and on the other by a fixed plate of arched profile that combines with the outer surface of the drum to create a rolling channel.

It happens with this type of method that when given operating speeds are exceeded by the filter tip attachment, cigarettes entering the rolling channel at an angular velocity of zero, referred to their own axes, are accelerated to a relatively high speed of rotation and subjected consequently to high stresses tending to spoil the cigarettes irreparably, with the loss of tobacco particles from their ends.

Employing a different method also embraced by the prior art, the rolling channel is created between the drum on the one hand, and on the other, a belt driven at a speed different to that of the drum and embodied usually in a flexible and resilient material. In this instance, however, the belt material tends to wear rapidly.

The object of the present invention is to provide a device for applying filters to cigarettes that will be unaffected by the drawbacks typical of prior art devices as described above.

DISCLOSURE OF THE INVENTION

The stated object is realized in a device according to the present invention for applying filters to cigarettes, of which the characterizing features are recited in claim 1 appended.

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

FIG. 1 illustrates a portion of a filter tip attachment, viewed schematically in elevation with certain parts omitted and comprising a device for applying filters to cigarettes embodied in accordance with the present invention,;

FIG. 2 shows an enlarged detail of FIG. 1;

FIG. 3 shows a part of FIG. 1, viewed from above and in a section taken on III-III with certain parts omitted;

FIG. 4 shows a detail of FIG. 2 in an enlarged and exploded view;

FIG. 5 shows a detail of FIG. 4 in a different embodiment;

FIG. 6 illustrates a portion of a filter tip attachment, viewed schematically in elevation with certain parts omitted and comprising the device of FIG. 1 in a different embodiment.

Referring to FIG. 1 of the drawings, 1 denotes a portion of a filter tip attachment, in its entirety, comprising a device for applying filters to cigarettes, denoted 2 in its entirety, 3 denotes a fluted drum 3 rotatable anticlockwise as viewed in FIG. 1, on which to advance assemblies 4 composed (as illustrated in FIG. 3) of two cigarettes 5 and a double length filter plug 6 interposed between the two cigarettes. The assemblies 4 are directed by the drum 3 through a transfer station 7 and into the device 2, of which the infeed stage includes a first conveyor 8 consisting in a roller 9, rotatable clockwise as viewed in FIG. 1 and furnished peripherally with a plurality of aspirating seats or grooves 10 each serving to accommodate a respective assembly 4 together with a tipping paper 11 cut from continuous strip by a rotary blade of conventional embodiment (not illustrated) operating in conjunction with the roller 9 at a point upstream of the transfer station 7.

Positioned in close proximity to the roller 9, downstream of the transfer station 7, is a flexible rolling conveyor 12 that combines with the outer cylindrical surface of the roller 9 to establish a rolling channel 13. The flexible rolling conveyor 12 is looped around first and second transmission means denoted 14 and 15 of which the first, upstream, comprises a first freely revolving return pulley 16 combining with the flexible conveyor 12 by which it is partly enveloped to create an infeed conveyor 17 preceding the rolling channel 13, whilst the second, downstream, comprises a second power driven return pulley 18 and, rigidly and concentrically associated with the pulley, a take-up roller 19 of which the periphery affords a plurality of recesses 20 placed to receive the assemblies 4 emerging from the rolling channel 13, each with a tipping paper 11 wrapped around the double filter plug 6 and the cigarettes 5 and denoted 4 a. The pulley 18 and roller 19 thus constitute an outfeed and take-up conveyor 21.

In operation, the peripheral speed of the conveying roller 9 is greater than the speed of the flexible conveyor 12 along the channel 13, thereby inducing the rolling action.

Also shown in FIG. 1 is a roller 22, indicated by phantom lines, rotatable about an axis parallel to the axis of the roller 19 by which the assemblies 4 a are taken up from the conveying roller 9 and serving to feed the assemblies 4 a on to further processing means not illustrated.

As discernible from the drawings, the outside face of the flexible conveyor 12, which can be fashioned as a web or belt of resilient and flexible material, is furnished with a plurality of rigid cladding elements 23 consisting, as illustrated in FIG. 5, of metal cleats 24 ordered one beside the next and disposed transversely to the selfsame conveyor 12. Positioned on the opposite inside face of the flexible conveyor 12, coinciding with each of the cleats 24, are fastening means 25 taking the form of blocks 26 secured to the respective cleats 24 by clamping means 27 such as screws or bolts.

In the preferred embodiment of FIG. 1, it will be seen that the rolling channel 13 is formed entirely between the cylindrical surface of the conveying roller 9 on the one hand and the corresponding branch of the flexible conveyor 12 on the other, presenting a curved profile; accordingly, the channel 12 is furnished with retaining means and with guiding and locating means denoted 28 and 29 respectively, in their entirety, by which the conveyor 12 is made to describe a path concentric with the roller 9 and the depth of the channel 13 maintained constant and substantially identical to the diameter of the cigarette and filter assemblies 4.

With reference in particular to FIGS. 3 and 4, the retaining means 28 consist in a plurality of magnetic elements 30 fashioned as discs and embedded in a pair of nonmagnetic parallel bars 31 cradled by an arched member 32 consisting also of nonmagnetic material and extending parallel to the rolling channel 13.

The function of the magnetic elements 30 is to interact with the cleats 24 and with the fastening means 25 and thereby attract the flexible conveyor 12 along the length of the rolling channel 13 in such a way as to maintain the correct position of the conveyor 12 relative to the conveying roller 9, as described above.

The guiding and locating means 29 comprise a plurality of freely revolving wheels 33 rotatable about axes parallel to the axis of the conveying roller 9 and offered in contact to the inside face of the flexible conveyor 12.

In the example of FIG. 3, the wheels 33 are ordered in three faces parallel to the two bars 31, which are interposed between the races of wheels 33. Each race comprises two rows of wheels 33 lying in parallel planes with each wheel 33 of each row partly overlapping one or two wheels of the parallel and adjacent row, so to afford substantially continuous support to the flexible conveyor 12. In particular, the inside face of the flexible conveyor 12 affords a toothed profile 34 in mesh with corresponding teeth afforded by the first and second pulleys 16 and 18 and by the freely revolving wheels 33, denoted 35, 36 and 37 respectively.

As illustrated in FIGS. 2 and 4, the surfaces of the cleats 24 combining to establish one face of the rolling channel 13 each present a reeded profile 38 that constitutes the rolling surface proper.

In addition, every second cleat 24 of the rolling surface, in the example illustrated, is furnished along the edge located downstream in the direction followed by the conveyor 12 along the channel 13, with a rib or lip 39 of which the function is to interact positively with each assembly 4 directed into the rolling channel 13 so as to initiate the rolling step brought about along the channel 13.

In the example of FIG. 5, more particularly, the adjoining edges of successive cleats 24 present a broken outline 40 and interlock one with the next in such a way as to prevent dust or foreign matter, typically tobacco particles, from fouling the parts of the flexible conveyor 12 beneath. In this instance the aforementioned rib or lip 39 will occupy a substantially intermediate position on the cleat 24.

Moreover, and with protection likewise in mind, the device 2 according to the invention is equipped with two guards 41, one only of which visible in FIG. 1, flanking the flexible conveyor 12 on either side and occupying respective vertical planes adjacent to the two return pulleys 16 and 18. The protected space between the two guards 41 will accommodate the drive for the live pulley 18.

Referring to FIGS. 1 and 2, it will be seen that the assemblies 4 enter the rolling channel 13 spaced apart at a first pitch p1 and reach the outfeed end of the channel 13 at a second pitch p2 shorter than the first. To the end of extracting specific and higher levels of performance from the filter tip attachment in terms of output, a further reduction in pitch is also necessary. This is obtained at the outfeed end of the rolling channel 13, at the moment of transferring the assemblies 4 a from the channel to the take-up roller 19: more exactly, the roller 19 is greater in diameter than the pulley 18 with which it is rigidly associated, and presents a predetermined number of recesses 20 spaced apart in such a manner as to shorten the distance between the advancing assemblies 4 a from the aforementioned second pitch p2 to a further selected pitch p3.

In the example of FIG. 6, the rolling channel 13 is created between two flexible conveyors 12, one on either side, embodied in entirely the same way as the conveyor 12 illustrated in FIG. 1, the channel 13 in this instance extending through a rectilinear path and the conveying roller 9 being replaced by a flexible conveyor 12 looped around two pulleys 42 and 43 identical to the pulleys 16 and 18 described previously. The pulley denoted 42 will be rigidly associated with a roller 44 presenting seats or grooves 45 similar to the seats or grooves 10 of the conveying roller 9, by which the assemblies 4 are taken up from the drum 3 and transferred to the rolling channel 13. 

1. A device for applying filters to cigarettes, comprising a first conveyor (8) serving to carry assemblies (4) composed of at least one cigarette (5) and a filter plug (6) placed end to end, and tipping papers (11) by which the assemblies (4) are joined permanently, also a rolling channel (13) of depth matched approximately to the diameter of the assemblies (4) received from the first conveyor (8), characterized in that the rolling channel (13) comprises a flexible rolling conveyor (12) at least on the one hand, looped around first and second transmission means (14, 15), and in that the rolling surface of the flexible conveyor (12) is furnished with a plurality of rigid elements (23).
 2. A device as in claim 1, wherein the rigid elements (23) comprise a plurality of cleats (24) ordered transversely one beside the next along the flexible conveyor (12) to provide a cladding.
 3. A device as in claim 2, wherein each cleat (24) is secured by respective fastening means (25) to the flexible conveyor (12).
 4. A device as in claim 3, wherein the fastening means (25) comprise a plurality of blocks (26) positioned on the side of the flexible conveyor (I 2) opposite to the cleats (24), each connected to a respective cleat (24) by clamping means (27).
 5. A device as in claim 1, wherein the rolling channel (13) comprises a first flexible conveyor (12) on the one hand, and a second flexible conveyor (12) on the other.
 6. A device as in claim 5, wherein the rolling channel (13) comprises a first flexible conveyor (12) on the one hand, and a second flexible conveyor (12) as in claims 2 to 4 on the other.
 7. A device as in claim 6, wherein the rolling channel (13) extends along a predetermined and substantially rectilinear rolling path.
 8. A device as in claim 7, wherein both of the flexible conveyors (12) are looped around respective first and second transmission means (14, 15) comprising respective return pulleys (16, 18; 42, 43), one of the transmission means (14, 15) further comprising an outfeed and take-up conveyor (21) positioned to receive the assemblies (4 a) emerging from the rolling channel (13).
 9. A device as in claim 2, wherein the rolling channel (13) extends along a predetermined and substantially curvilinear rolling path.
 10. A device as in claim 9, wherein the rolling channel (13) is created between a roller (9) with aspirating seats (10) on the one hand, coinciding with the first conveyor (8), and a flexible conveyor (12) on the other.
 11. A device as in claim 10, wherein the first and second transmission means (14, 15) of the flexible conveyor (12) comprise a first and a second return pulley (16, 18), the first transmission means (14) establishing an infeed conveyor (17), the second transmission means (15) further comprising an outfeed and take-up conveyor (21) disposed coaxially with the respective second return pulley (18) and serving to receive the assemblies (4 a) emerging from the rolling channel (13).
 12. A device as in claim 11, comprising retaining means (28) and guiding and locating means (29) associated with the flexible conveyor (12) and positioned on the side of the flexible conveyor (12) opposite from the channel (13).
 13. A device as in claim 12, wherein the retaining means (28) comprise a plurality of magnetic elements (30) interacting with the fastening means (25) and/or the cleats (24).
 14. A device as in claim 12, wherein the guiding and locating means (29) comprise a plurality of freely revolving wheels (33) offered in contact to the surface of the flexible conveyor (12).
 15. A device as in claim 14, wherein the magnetic elements (30) are carried by at least one member (32) of nonmagnetic material extending parallel to the rolling channel (13) and interposed between two sets of guiding and locating wheels (33).
 16. A device as in claim 15, wherein the single sets of guiding and locating wheels (33) are ordered in respective rows occupying parallel planes, with each wheel (33) of each row partly overlapping at least one wheel of the adjacent row.
 17. A device as in claim 16, wherein the flexible conveyor (12) presents a toothed profile (34) in mesh with teeth (37) presented by the guiding and locating wheels (33) and with teeth (35, 26) presented by the pulleys (16, 18).
 18. A device as in claim 17, wherein each of the cleats (24) presents a rolling surface fashioned with a reeded profile (38).
 19. A device as in claim 18, wherein at least one cleat (24) per given unit number of cleats is furnished with at least one rib or lip (39) serving to initiate the rolling action internally of the rolling channel (13).
 20. A device as in claim 8, wherein the outfeed and take-up conveyor (21) in receipt of the assemblies (4 a) from the rolling channel (13) comprises a roller (19) by which the emerging assemblies (4 a) are taken up and distanced selectively one from the next.
 21. A device as in claim 20, wherein the take-up roller (19) functions as a means by which to shorten the distance between successive assemblies (4 a) emerging from the rolling channel (13).
 22. A device as in claim 21, wherein the take-up roller (19) presents peripheral recesses (20) spaced apart at a distance less than the distance separating successive assemblies (4 a) emerging from the rolling channel (13).
 23. A device as in claim 22, wherein the take-up roller (19) is rigidly associated with the second return pulley (18) of the flexible conveyor (12). 